Online social networking applications, such as Facebook and Twitter are very much used in modern user devices for communication among users. With user devices in communication networks are meant e.g. mobile devices, such as smart phones. One of the main reasons for the popularity of these applications is that they enrich communication among users of the applications, for example allow users to easily share information.
As a user of a communication service, it is of interest to share content with other users of that service. For example, a user may want to invite people to participate in a planned activity, or he/she may want to share information regarding a certain topic with people in his/her vast, or narrower, circle of acquaintances. This may be achieved by sending messages to contacts stored in a contact repository, such as an address book of the user's user device, or in a contact list of a mobile application, such as Facebook. If the user sends a message, such as an invitation or information to everyone in his/her contact list, some of his/her contacts will receive a message that is not at all relevant and of interest to them. Consequently, the user will need to specify a limited selection of contacts for receiving the message, before sending the message. This may be accomplished by manually picking out certain contacts from a contact repository, such as the address book of the user's user device or the contact list of the user's Facebook account. This may be a rather tedious and time-consuming procedure. As an example, the average number of contacts in Facebook for one user is 130, as of 2011. Further, the user may have contacts in different types of communication applications, such as the contact list of the user device, the Facebook account, the email account(s) etc. It is thus a problem that it is a tedious and time-consuming procedure to manually identifying receivers of a message, such as an invitation or information.